How can I insulate an interior back wall that is NOW an exterior back wall?
I had an interior porch torn down and had an exterior porch built. Now the back wall to the building is letting in cold air. I need to insulate the building.
When renovating exterior walls you need to observe the normal practices for wall assemblies or ‘control layers’, meaning air barriers, vapor barriers and thermal barriers (insulation). But that needs to meet your local climate conditions, so, what is your climate zone? Read more here – How to Find Your Building Climate Zone.
And please describe what your walls are like now, so let us know if they are – open with access to the studs, 2x4 or 2x6, if there is sheathing, weather barrier, siding etc. It may be a simple matter of adding batt insulation, and based on your ‘cold air’ comment, you are likely not in a hot humid climate, so you would likely need a vapor barrier on the warm side of the insulation. Learn more here in our Building science for wall design made easy – Video